<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <style>
    body,
    ul {
      margin: 0;
      padding: 0;
    }
    body {
      width: 24rem;
      height: 13.5rem;
      box-sizing: border-box;
      border: 0.0375rem solid red;
    }
    ul {
      width: 100%;
      height: 100%;
      list-style: none;

      display: flex;
      flex-direction: row;
      flex-wrap: wrap;
    }
    li {
      width: 33.333%;
      height: 50%;
      box-sizing: border-box;
      border: 2px solid green;
      font-size: 0.375rem;
    }
  </style>
  <body>
    <!-- 
      .动态设置HTML根字体大小和body字体大小（lib_flexible.js）
        1.将设计稿的宽度（1920）平均分成24等分，每一份为80px
        2.HTML字体大小就设置为80px，即1rem = 80px， 24rem = 1920px
        3.body字体大小设置为16px
        4.安装cssrem插件，root font size设置为80px.这个是px单位转rem的参考值
     -->
    <ul>
      <li>1</li>
      <li>2</li>
      <li>3</li>
      <li>4</li>
      <li>5</li>
      <li>6</li>
    </ul>
    <script src="./lib_flexible.js"></script>
  </body>
</html>
